NOTES for Tit 1:13-14
It would seem that Paul, being himself a Jew who knew his tradition very well, should not have spoken this way about those who called people to follow it and strictly observe all the religious prescriptions of Judaism. But the point is precisely that after meeting the Risen One, Paul never again absolutized his own religion. For him Judaism ceased to be a religion; it became for him a spiritual path, the path of the inner Torah, which is completed in Christ, who revealed to the world the model of the living Torah.
The apostle never denied this path. The problem, however, was that the newly appeared "teachers of the Torah" who had appeared in large numbers in the Church were not thinking about any path and most of all knew nothing about it properly. They liked religion as such; they connected their path with religiosity and with strict, formal fulfillment of all religious prescriptions.
Paul, from his own experience, knew perfectly well that religiosity as such is a spiritual dead end. It leads nowhere and only imitates spiritual life, preserving some of its outward forms and reproducing them outwardly. And the apostle considered it necessary to do everything possible to keep any of those who had turned to Christ and found Him from ending up in such a dead end. He was absolutely sure: Christianity is not a religion, but life in the Kingdom, and religiosity is not needed for this life.
Of course, a religious person too can enter the Kingdom, but on one condition: he does not absolutize his religion and does not impose it on others. Not even because imposing one's religion on others is at least incorrect toward them, but because a person who acts this way himself hopes in his religiosity more than in Christ; otherwise he would not connect with it his own salvation and the salvation of those whom he wants to make as religious as he himself is. It is against this distortion of spiritual and church life that Paul warns everyone, always and very persistently - because here the issue is a substitution by which one can easily lose the Kingdom, and therefore salvation.